
/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 *版权所有2002-2017原作者。
 *
 *根据Apache许可证2.0版（“许可证”）许可；
 *除非符合许可证的规定，否则您不得使用此文件。
 *您可以在以下网址获取许可证副本
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 *除非适用法律要求或书面同意，否则软件
 *根据许可证分发是在“按原样”的基础上分发的，
 *无任何明示或暗示的保证或条件。
 *有关管理权限的特定语言，请参阅许可证
 *许可证下的限制。
 */

package org.springframework.context.weaving;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.instrument.classloading.LoadTimeWeaver;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * {@link org.springframework.beans.factory.config.BeanPostProcessor}
 * implementation that passes the context's default {@link LoadTimeWeaver}
 * to beans that implement the {@link LoadTimeWeaverAware} interface.
 *
 * <p>{@link org.springframework.context.ApplicationContext Application contexts}
 * will automatically register this with their underlying {@link BeanFactory bean factory},
 * provided that a default {@code LoadTimeWeaver} is actually available.
 *
 * <p>Applications should not use this class directly.
 *
 * @author Juergen Hoeller
 * @since 2.5
 * @see LoadTimeWeaverAware
 * @see org.springframework.context.ConfigurableApplicationContext#LOAD_TIME_WEAVER_BEAN_NAME
 */
/**
 *｛@link org.springframework.beans.factory.config.BeanPostProcessor｝
 *传递上下文默认｛@link LoadTimeWeaver｝的实现
 *到实现{@link LoadTimeWeaverWare}接口的bean。
 *
 *＜p＞｛@link org.springframework.context.ApplicationContext应用程序上下文｝
 *将自动将其注册到其底层{@link BeanFactory bean factory}，
 *前提是默认的{@code LoadTimeWeaver}实际上是可用的。
 *
 *<p>应用程序不应直接使用此类。
 *
 *@作者Juergen Hoeller
 *@自2.5起
 *@参见LoadTimeWeaverware
 *@参见org.springframework.context.ConfiguratableApplicationContext#LOAD_TIME_WEAVER_BEAN_NAME
 */
public class LoadTimeWeaverAwareProcessor implements BeanPostProcessor, BeanFactoryAware {

	@Nullable
	private LoadTimeWeaver loadTimeWeaver;

	@Nullable
	private BeanFactory beanFactory;


	/**
	 * Create a new {@code LoadTimeWeaverAwareProcessor} that will
	 * auto-retrieve the {@link LoadTimeWeaver} from the containing
	 * {@link BeanFactory}, expecting a bean named
	 * {@link ConfigurableApplicationContext#LOAD_TIME_WEAVER_BEAN_NAME "loadTimeWeaver"}.
	 */
	/**
	 *创建一个新的｛@code LoadTimeWeaverwareProcessor｝，它将
	 *从包含中自动检索｛@link LoadTimeWeaver｝
	 *｛@link BeanFactory｝，需要一个名为
	 *｛@link可配置应用程序上下文#LOAD_TIME_WEAVER_BEAN_NAME“loadTimeWeaver”｝。
	 */
	public LoadTimeWeaverAwareProcessor() {
	}

	/**
	 * Create a new {@code LoadTimeWeaverAwareProcessor} for the given
	 * {@link LoadTimeWeaver}.
	 * <p>If the given {@code loadTimeWeaver} is {@code null}, then a
	 * {@code LoadTimeWeaver} will be auto-retrieved from the containing
	 * {@link BeanFactory}, expecting a bean named
	 * {@link ConfigurableApplicationContext#LOAD_TIME_WEAVER_BEAN_NAME "loadTimeWeaver"}.
	 * @param loadTimeWeaver the specific {@code LoadTimeWeaver} that is to be used
	 */
	/**
	 *为给定的创建一个新的{@code LoadTimeWeaverwareProcessor}
	 *｛@link LoadTimeWeaver｝。
	 *<p>如果给定的{@code loadTimeWeaver}是{@code null}，则
	 *｛@code LoadTimeWeaver｝将自动从包含
	 *｛@link BeanFactory｝，需要一个名为
	 *｛@link可配置应用程序上下文#LOAD_TIME_WEAVER_BEAN_NAME“loadTimeWeaver”｝。
	 *@param loadTimeWeaver要使用的特定｛@code loadTimeWeaver｝
	 */
	public LoadTimeWeaverAwareProcessor(@Nullable LoadTimeWeaver loadTimeWeaver) {
		this.loadTimeWeaver = loadTimeWeaver;
	}

	/**
	 * Create a new {@code LoadTimeWeaverAwareProcessor}.
	 * <p>The {@code LoadTimeWeaver} will be auto-retrieved from
	 * the given {@link BeanFactory}, expecting a bean named
	 * {@link ConfigurableApplicationContext#LOAD_TIME_WEAVER_BEAN_NAME "loadTimeWeaver"}.
	 * @param beanFactory the BeanFactory to retrieve the LoadTimeWeaver from
	 */
	/**
	 *创建一个新的{@code LoadTimeWeaverwareProcessor}。
	 *<p>｛@code LoadTimeWeaver｝将从中自动检索
	 *给定的{@linkBeanFactory}，期望一个名为
	 *｛@link可配置应用程序上下文#LOAD_TIME_WEAVER_BEAN_NAME“loadTimeWeaver”｝。
	 *@param beanFactory要从中检索LoadTimeWeaver的beanFactory
	 */
	public LoadTimeWeaverAwareProcessor(BeanFactory beanFactory) {
		this.beanFactory = beanFactory;
	}


	@Override
	public void setBeanFactory(BeanFactory beanFactory) {
		this.beanFactory = beanFactory;
	}


	@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
		if (bean instanceof LoadTimeWeaverAware) {
			LoadTimeWeaver ltw = this.loadTimeWeaver;
			if (ltw == null) {
				Assert.state(this.beanFactory != null,
						"BeanFactory required if no LoadTimeWeaver explicitly specified");
				ltw = this.beanFactory.getBean(
						ConfigurableApplicationContext.LOAD_TIME_WEAVER_BEAN_NAME, LoadTimeWeaver.class);
			}
			((LoadTimeWeaverAware) bean).setLoadTimeWeaver(ltw);
		}
		return bean;
	}

	@Override
	public Object postProcessAfterInitialization(Object bean, String name) {
		return bean;
	}

}
